Ap JAVA semester 1 final

WIP

Attributes

Instance variable, properties of object. Ex: Class = dog, attributes = color, breed, age

Behavior

methods (ex: turnLeft() )

Case sensitive

Uppercase vs - lowercase. HELLO is diff than hello

Run-time error

logic error, ex in painter there is a paint command but they are out of paint

Variable

attribute

Primitive type

predefined. no capitalization. int, double, char, boolean.

Parameter

variable in method constructors ex: color in public void paint(String color){

Argument

value of the parameter. ex: “white” in painter.paint(“white”);

Void method

does not have a return type, instead does an action.

Encapsulation

combining data and functions, etc, into one class. Basically using private with get and set methods

Constructor

Public method for instantiating an object. Ex: public Dog(int age, String breed){

Truncation

int divided by an int slices off the decimal instead of rounding

Concatenation

slapping to strings together. Can use +=

int/0 vs double/0

double will return infinity, int will make your planes explode

compound assignment operator

shortcuts. +=, -=, *=. Ex: if int a = 4, a+= 6 will yield 10. same as a = a + 6

mod operator

%. gives you the truncated remainder

casting

assign a value of one type to another. Ex: int num = (int) 5.2; //num is now 5

math random

(int)(Math.random() * range) + min

object class

superclass

toString()

to return an object in string format to be readable. Ex: public String toString(){ return variable + “ “;}

escape sequences

\n = new line, \\ = backslash, \” = double quote

parsing

dividing texts into different parts w/substring

.compareTo

returns the int value of subtracting the two strings

class methods

can be called without creating a class object

instance methods

method that requires an object of a class to be created to be called

static

in class methods

overloading

defining two or more constructors with the same name but different signatures

iteration statement

statements that repeatedly perform a block of code. Ex: while

selection statement

statements that perform a block of code once under certain circumstances. if statements

demorgans laws

!(A && B) = !A || !B. !> is <=, !< is >=, vise versa

alias

a different name assigned to the same object. They are strings that are ==

non alias

different objects with the same name. These use .equals

for loops

(ex:) for(int i = #; i<#; i++){code}

abstraction

condensing/simplifying, like classes with constructors being created in a class, or assigning variables names like int age = 76 for ex

accessor methods

get() method

mutator methods

set() method

reference variable

an object created with all its attributes being its own thing when stored as an object.

shadowing

local (private) variables shadow global (public) variables with the same name. Basically just giving it a default I guess

returns character index

.charAt()

see if one string has the same sequence of characters

.contains()

find number character is at

indexOf()

find last number character is at

.lastIndexOf()

get actual length

.length()-1;

floor

floor(x), rounds down, returns double

ceiling

ceil(x), rounds up, returns double

== vs =

== for checking something (returning a boolean). ex: if(a == b). = for setting equal